I really like my WRT54G and have had no problem with it. In fact, if you get brave, you can install a third party firmware (such as Sveasoft Alchemy) that will give you features only available on expensive wireless routers. Check out
http://wrt54g.net/ for more information. Also, you can use Firewall Builder to make a custom firewall if you've install Alchemy.
One important thing to note is that there are different versions of the WRT54G and not all 3rd party firmware works on all versions.